I just picked up a new walbro LME 57 carb that has an old core tag on it. The LME 36 I have is the original carb from my 69 Sears Suburban.If you look at the pic, you can see a small brass plug near the bottom of the choke butterfly on the LME 57 (the carb on the left).The plug has a small hole in the center restricting flow.The sears Suburban 12 LME 36 does not have this plug.Is the LME 57 with the brass plug intended for a smaller engine?

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In my Walbro parts and service manual it shows the LME 57 as a carb for Allied Pacific and equipment list as a Drive cycle.Your LME 36 is listed for a HH120.The only difference is the venturi size.The 36 shows 21.80(mm),the 57 shows 19.05(mm).Here is the parts list and cross reference that shows the difference

Thanks for the info, I appreciate it. I disassembled both carbs and you can see the difference in the size of the venturi. Here is a pic of an LME 36 and an LME 34. Both have 55 cast into them and both are for the HH120.